The top-level dir of the chroot is /var/chroot/ia32, but I have a symbolic link on /emul/linux-ia32 pointing to /var/chroot/ia32. Anyway, I've tried with the --expert option, specifying /var/chroot/ia32, with the same result. I install the driver by running the installer, with no options at all (except for the time I tried in expert mode).